Influences of thermal treatment temperature on microstructures and properties of glass-ceramics from gold tailings

Abstract

Use CaO-Al₂O₃-SiO₂ glass-ceramics from gold tailings in Hanyin as main raw materials, which were prepared by a melting method. In this paper, the effects of nucleation temperature and crystallization temperature on microstructures and properties of the glass-ceramic specimens were investigated. The thermal property of the glass-ceramics was discussed by differential scanning calorimetry (DSC), and microstructure was characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Methods of a 4-point bending strength test, DIL-402C dilatometer and Archimedes method were used to determine the bending strength, thermal expanding coefficient and density of glass-ceramics. The experiment results indicated that the optimal properties of glass-ceramics were obtained by nucleation at 800 °C for 2 h, and then crystalling at 950 °C for 3 h. XRD analyses demonstrated that the main phase of gold tailings glass-ceramics was augite and diopside (CaMgSi₂O₆), and the minor phase was potassium iron silicate (KFeSi₂O₆). The bending strength, density and thermal expanding coefficient of the glass-ceramics were 128 MPa, 2.840 g/cm³ and 7.85 × 10⁻⁶/°C, respectively.

Keywords:

• Thermal treatment temperature
• gold tailings
• glass-ceramics
• melting method

Additional information

Funding

This work was supported from Longyuan Youth Innovation and Entrepreneurship Talent (team) Project (2020RCXM125), Gansu Province higher education Innovation Ability Enhancement Project (2019A-248), Industrial support and guidance project of colleges and universities in Gansu Province (2019C-20), and Innovation ability improvement project of colleges and universities in Gansu Province (2020B-375).